Terra Linna maintenance

[Bernard Chenery]

Hi folks, There is a couple of pictures I have taken of the underfloor bow section area. It is an accumulation of wood shavings, dust, leaf and assorted bits. Most of the time it would be damp and as such would be slowly causing rot to develop along the keel.

As the  cover is loose rain water will collect in the bilge adding to the problem. I will start checking this out next Thursday.

[Andrew Perkins]

Hi Bernie, I suggest you scrape off that loose paint it is sometimes an indication of caustic degradation which is cancer of traditional wooden boats , my understanding is it is caused by water ingress around metal fasteners and fittings where water seeps in over time the oxygen level varies through the timber from the underwater outside to the inside which causes a small electrolytic cell to form around the fastener forming chloride ions and when they meet the  oxygenated air on the inside the chloride ions form a caustic solution which degrades the timber similar to the paper pulp making process . It is more common around fittings like skin fittings and stern tubes that are protected by anodes but I have seen it around nails and keel bolts etc. If you pour some vinegar on a suspected section it will fizz .

Old jetty structures are a good example you will sometimes see the remains of a steel bolt sitting loosely in a large hole through a timber pile !

Andrew

[Bernard Chenery]

Thanks for the info. I will investigate ‘ caustic degradation’ of the area concerned. At the last slipping there was one spot at the garboard/keel junction that continued to weep water for a couple of days after removing TL out of the water. After the weeping stopped the area was inspected and as there did not appear to be any rot or damage  the area was rubbed down and repainted.

[Peter Higgs]

Bernie this seems to be in the right spot to me.

[Author]

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